A finished, “printed” blood vessel is shown at Organovo. Blood vessels are the company’s initial focus. The knowledge gained is expected to help in building other tissue types. K.C. Alfred / Union-Tribune

A finished, “printed” blood vessel is shown at Organovo. Blood vessels are the company’s initial focus. The knowledge gained is expected to help in building other tissue types.

The challenge was to build a new kind of machine: a three-dimensional “printer” that would enable scientists to one day build human organs cell by cell.

A small San Diego biotechnology company, Organovo, commissioned the system last year, aiming to advance its own work in tissue regeneration while also selling additional machines to academic researchers.

Engineers at custom automation company Invetech went to work, tackling challenges such as how to make the device small enough to be practical and precise enough to make actual tissues.

The machine arrived in San Diego in the fall, and Organovo is optimistic about its potential.

Chief Executive Keith Murphy said the primary focus initially is blood vessels, with several years of animal and human testing necessary before the company would have an actual medical product. But gaining expertise in building blood-vessel networks would help in building other tissue types, he added.

“Anything that’s a tissue you can contemplate,” Murphy said. “Longer-term, we think this technology can be critical in solving the organ shortage.”

The machine sits in a laboratory cabinet at Organovo’s offices in Sorrento Valley. To run it, an operator types instructions into a computer, which guides two automated, laser-calibrated print heads.

Then the print heads go to work, moving up and down and side to side to place cells in the desired configuration. While one places the actual cells, the other builds a “scaffold” that holds them in place before the tissue starts to form.

It takes about an hour for the machine to do its work, with a typical blood vessel for use in research usually about 5 centimeters long.

Then the cells go into an incubator, where they start to form the tissue over the next 24 hours or so. From there, they go into a “bioreactor,” where the tissue strengthens over a period of weeks until it’s theoretically ready for transplant into a patient.

Product manager Daniel Schumann of Invetech said the company was drawn to the project by the potentially revolutionary applications of the machine. Over the years, the Australia-based company, which has an office in San Diego, has been involved in projects ranging from ultrasophisticated laboratory equipment to an improved version of the mousetrap.

“We’ve been doing this for 30 years,” Schumann said. “We’ve got 200 engineers on our staff. We’ve done thousands of projects. And still, we looked at this and said: ‘Wow, this is really something. This could really be a breakthrough product.’ ”

Ultimately, the idea would be for surgeons to have tissue on demand for various uses, but there remains a lot of work for that to happen. Organovo is still a small company, with five employees plus a few more part-timers and consultants.

The company was formed in 2007 by Gabor Forgacs, a professor of theoretical physics at the University of Missouri. At first, it operated from Missouri on a $5 million grant Forgacs received to develop the technology.

The company has since raised more money from “angel” investors, and it moved to San Diego last year.